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Abstract:

An etalon includes a first substrate, a second substrate facing the first
substrate, a fixed mirror provided on a surface of the first substrate
that faces the second substrate, a movable mirror provided on the second
substrate and facing the fixed mirror via an inter-mirror gap, and a
first electrode provided on the surface of the first substrate that faces
the second substrate. A first multilayer stopper portion is provided by a
portion of the first electrode being stacked with at least a portion of
an outer circumferential edge of the fixed mirror.

Claims:

1. A variable wavelength interference filter comprising: a first
substrate; a second substrate facing the first substrate; a first
reflection film provided on a first surface of the first substrate, the
first surface facing the second substrate; a second reflection film
provided on the second substrate, the second reflection film facing the
first reflection film and being separated therefrom by a predetermined
gap; and a first electrode provided on the first surface of the first
substrate; wherein a first multilayer stopper portion is provided by a
portion of the first electrode being stacked with at least a portion of
an outer circumferential edge of the first reflection film.

2. The variable wavelength interference filter according to claim 1,
further comprising a second electrode provided on a surface of the second
substrate, the surface facing the first substrate, wherein a second
multilayer stopper portion is provided by a portion of the second
electrode being stacked with at least a portion of an outer
circumferential edge of the second reflection film.

3. The variable wavelength interference filter according to claim 1,
wherein a second electrode facing the first electrode is provided on the
second substrate, and the first electrode and the second electrode are
drive electrodes which change a dimension of the gap as a voltage is
applied thereto.

4. The variable wavelength interference filter according to claim 1,
wherein a second electrode facing the first electrode is provided on the
second substrate, and the first electrode and the second electrode are
electrostatic capacitance measuring electrodes which measure an
electrostatic capacitance held between the first electrode and the second
electrode.

5. The variable wavelength interference filter according to claim 1,
wherein the first electrode is an electric charge removing electrode
which removes an electric charge from the first reflection film.

6. The variable wavelength interference filter according to claim 1,
wherein in the first multilayer stopper portion, the first reflection
film and the first electrode are stacked in this order from the first
substrate.

7. The variable wavelength interference filter according to claim 1,
wherein in the first multilayer stopper portion, the first electrode and
the first reflection film are stacked in this order from the first
substrate.

8. The variable wavelength interference filter according to claim 1,
wherein the first electrode is made of a non-light-transmissive material,
and the first multilayer stopper portion is provided in a ring shape
prescribing a light transmitting area for incident light transmitted
through the first reflection film and the second reflection film, as
viewed in a plan view of the first substrate and the second substrate.

9. The variable wavelength interference filter according to claim 8,
wherein the second electrode is provided on a surface of the second
substrate, the surface facing the first substrate, a portion of the
second electrode is stacked on an outer circumferential edge of the
second reflection film to form a ring-shaped second multilayer stopper
portion, and an inner diameter dimension of the first multilayer stopper
portion is smaller than an inner diameter dimension of the second
multilayer stopper portion, as viewed in the plan view.

11. An optical analysis device comprising: the optical module according
to claim 10; and an analytical processing unit which analyzes an optical
property of the inspection target light, based on light received by the
light receiving unit of the optical module.

12. A variable wavelength interference filter comprising: a first
reflection film; a second reflection film facing the first reflection
film with a predetermined gap therebetween; and a first electrode;
wherein a first protrusion is provided by a portion of the first
electrode being stacked with at least a portion of an outer
circumferential edge of the first reflection film.

13. The variable wavelength interference filter according to claim 12,
further comprising a second electrode facing the first electrode, wherein
a second protrusion is provided by a portion of the second electrode
being stacked with at least a portion of an outer circumferential edge of
the second reflection film.

14. A variable wavelength interference filter comprising: a first
reflection film; a second reflection film facing the first reflection
film with a predetermined gap therebetween; and a protrusion provided by
an electrode being stacked with at least a portion of an outer
circumferential edge of the first reflection film, the protrusion being
adapted to prevent the first reflection film and the second reflection
film from sticking to each other.

15. A variable wavelength interference filter comprising: a first
reflection film; a second reflection film facing the first reflection
film with a predetermined gap therebetween; and a protrusion provided on
an outer circumferential edge of the first reflection film; wherein G1 is
a width of the gap, G2 is a width of a space between the protrusion and
the second reflection film, and G1>G2.

Description:

BACKGROUND

[0001] 1. Technical Field

[0002] The present invention relates to a variable wavelength interference
filter, an optical module including the variable wavelength interference
filter, and an optical analysis device including the optical module.

[0003] 2. Related Art

[0004] In the related art, a variable interference device (variable
wavelength interference filter) is known in which reflection films face
each other across a predetermined gap. The reflection films are arranged
on surfaces of a pair of substrates that face each other (see, for
example, JP-A-1-94312).

[0005] In the variable wavelength interference filter described in
JP-A-1-94312, electrodes for adjusting the gap are arranged to face each
other by locating them on the surfaces of the pair of reflection films
that face each other. As a drive voltage is applied to each electrode,
the gap can be adjusted by electrostatic attraction. Thus, the variable
wavelength interference filter only transmits light with a specific
wavelength corresponding to the gap. That is, the variable wavelength
interference filter performs multiple interference of incident light
between the pair of reflection films and transmits only light with a
specific wavelength that is intensified by the multiple interferences
between the reflection films.

[0006] While manufacturing such a variable wavelength interference filter,
however, there is a risk that the reflection films may stick to each
other when the substrates are bonded to each other. Also, there is a risk
that the reflection films may stick to each other when the gap is
adjusted or due to an impact or the like when an external force is
applied. Such sticking of the reflection films causes damage to the
surfaces of the reflection films and therefore lowers the optical
properties (transmittance and reflectance) of the reflection films.

[0007] To prevent the reflection films from sticking to each other, it is
conceivable to provide a protrusion near the reflection films.

[0008] However, if such a protrusion is to be provided, a process of
providing the protrusion is separately needed in the process of
manufacturing the variable wavelength interference filter. Therefore,
there is a problem in that the configuration becomes complicated.

SUMMARY

[0009] An advantage of some aspects of the invention is that a variable
wavelength interference filter, an optical module and an optical analysis
device are provided in which reflection films can be prevented from
sticking to each other by a simple configuration.

[0010] An aspect of the invention is directed to a variable wavelength
interference filter including: a first substrate; a second substrate
facing the first substrate; a first reflection film provided on a first
surface of the first substrate, the first surface facing the second
substrate; a second reflection film provided on the second substrate and
facing the first reflection film with a predetermined gap therebetween;
and a first electrode provided on the first surface of the first
substrate. A first multilayer stopper portion is provided by stacking a
portion of the first electrode and at least a portion of an outer
circumferential edge of the first reflection film.

[0011] According to this aspect of the invention, the first multilayer
stopper portion formed by stacking a portion of the first electrode and
at least a portion of the outer circumferential edge of the first
reflection film is provided. Thus, the dimension between the first
multilayer stopper portion and the second reflection film is smaller than
the dimension of the gap between the reflection films. Therefore, when
the gap dimension between the reflection films is reduced, the first
multilayer stopper portion and the second reflection film contact each
other. Thus, the reflection films can be prevented from sticking to each
other.

[0012] Also, according to this aspect of the invention, since the first
multilayer stopper portion is formed by stacking the first electrode and
the first reflection film, the aforementioned protrusion need not be
provided separately on the reflection films and can be provided by
implementing the process of forming the first reflection film and the
first electrode. Therefore, the manufacturing process can be simplified
and a simple configuration can be realized.

[0013] In the variable wavelength interference filter, it is preferable
that a second electrode is provided on a surface of the second substrate
that faces the first substrate, and that a second multilayer stopper
portion be provided by stacking a portion of the second electrode and at
least a portion of an outer circumferential edge of the second reflection
film.

[0014] According to this configuration, the second multilayer stopper
portion is formed on the second substrate. In such a configuration, since
the second multilayer stopper portion which prevents the reflection films
from sticking to each other is provided on the second substrate side, the
reflection films can be more securely prevented from sticking to each
other.

[0015] Here, as viewed in a plan view of the first substrate and the
second substrate, if the second multilayer stopper portion is formed at a
position overlapping the first multilayer stopper portion, the first
multilayer stopper portion and the second multilayer stopper portion abut
each other and can prevent the first and second reflection films from
contacting each other. In this case, a gap is provided between the first
substrate and the second substrate, corresponding to the total of a
thickness dimension of the first multilayer stopper portion and a
thickness dimension of the second multilayer stopper portion. Therefore,
the gap dimension between the reflection films can be made greater and
the contacting and sticking of the reflection films can be more securely
prevented than, for example, in the case where the reflection films are
prevented from contacting each other by the first multilayer stopper
portion alone.

[0016] Also, the first multilayer stopper portion and the second
multilayer stopper portion may be provided at positions that do not
overlap each other at all, as viewed in the plan view. In this case, as
compared with the case where the reflection films are prevented from
contacting and sticking to each other by the first multilayer stopper
portion alone, the area of the stopper portion for preventing the
reflection films from contacting and sticking to each other is increased
by the provision of the second multilayer stopper portion, and the
stopper portions can counter a greater stress.

[0017] In the variable wavelength interference filter, it is preferable
that a second electrode facing the first electrode is provided on the
second substrate, and that the first electrode and the second electrode
are drive electrodes which change a dimension of the gap as a voltage is
applied thereto.

[0018] According to this configuration, the first electrode and the second
electrode are drive electrodes and therefore can also function as a gap
changing unit which changes the dimension of the gap. That is, in the
process of manufacturing the variable wavelength interference filter, the
need for a process of separately providing the aforementioned protrusion
can be eliminated and the first multilayer stopper portion can be easily
formed by the process of forming the first reflection film and the
process of forming the drive electrodes. Thus, a simple manufacturing
process can be realized and the structure can be simplified.

[0019] In the variable wavelength interference filter, it is preferable
that a second electrode facing the first electrode is provided on the
second substrate, and that the first electrode and the second electrode
are electrostatic capacitance measuring electrodes which measure an
electrostatic capacitance held between the first electrode and the second
electrode.

[0020] According to this configuration, the first electrode and the second
electrode function as electrostatic capacitance measuring electrodes. In
the variable wavelength interference filter provided with such
electrostatic capacitance measuring electrodes, the gap between the first
reflection film and the second reflection film can be calculated by
measuring the quantity of electric charge held by the first electrode and
the second electrode. Therefore, the wavelength of light extracted by the
variable wavelength interference filter can be found accurately. By
setting a gap between the first reflection film and the second reflection
film based on this electrostatic capacitance, a desired gap can be
accurately set as the gap between the reflection films.

[0021] Moreover, in the process of manufacturing the variable wavelength
interference filter, the first multilayer stopper portion can be easily
formed by the process of forming the first reflection film and the
process of forming the electrostatic capacitance measuring electrodes.

[0022] In the variable wavelength interference filter, it is preferable
that the first electrode is an electric charge removing electrode which
removes an electric charge from the first reflection film.

[0023] According to this configuration, the first electrode functions as
an electric charge removing electrode which removes an electric charge
from the first reflection film. Also, when the dimension of the gap
between the reflection film is decreased and the first multilayer stopper
portion contacts the second reflection film, an electric charge held in
the second reflection film can also be released from the electric charge
removing electrode of the first multilayer stopper portion. Therefore,
electrostatic attraction due to the electric charges held in the first
reflection film and the second reflection film does not occur and the gap
between the reflection films can be set with a desired gap dimension.

[0024] In the variable wavelength interference filter, it is preferable
that, in the first multilayer stopper portion, the first reflection film
and the first electrode are stacked in this order from the first
substrate.

[0025] Generally, a reflection film deposited on a substrate has a problem
in that an outer circumferential edge part thereof can be detached
relatively easily and the reflection film deteriorates easily. However,
according to this configuration, the first multilayer stopper portion is
configured so that the first electrode is stacked on the first reflection
film. Therefore, the first electrode securely protects the edge part of
the first reflection film and deterioration of the first reflection film
can be prevented.

[0026] In the variable wavelength interference filter, it is preferable
that, in the first multilayer stopper portion, the first electrode and
the first reflection film are stacked in this order from the first
substrate.

[0027] According to this configuration, in the first multilayer stopper
portion, the first electrode and the first reflection film are stacked in
this order from the first substrate. According to this, since the first
reflection film is deposited after the first electrode is deposited on
the first substrate, the process of forming the first reflection film can
be shifted further to a later stage and damage to the first reflection
film during the manufacturing process can be prevented further.

[0028] Also, in the case where the first reflection film is, for example,
a dielectric multilayer film in which insulating layers of SiO2,
TiO2 and the like are stacked, and the second electrode facing the
first electrode is provided on the second substrate, if the entire area
facing the second electrode, of the first electrode, is covered with the
first reflection film to form the first multilayer stopper portion, the
first reflection film can be used as an insulating layer. In this case,
the first multilayer stopper portion can prevent the reflection films
from contacting and sticking to each other and can also prevent
inconvenience such as discharge or leak between the first electrode and
the second electrode.

[0029] In the variable wavelength interference filter, it is preferable
that the first electrode is made of a non-light-transmissive material,
and that the first multilayer stopper portion is provided in a ring shape
prescribing a light transmitting area for incident light transmitted
through the first reflection film and the second reflection film, as
viewed in a plan view of the first substrate and the second substrate.

[0030] The non-light-transmissive material in this description means a
material that does not transmit light of a wavelength range that is a
measuring target of the variable wavelength interference filter.
Therefore, if the wavelength range that is a measuring target is visible
light, a metallic material that can transmit infrared rays and does not
transmit a visible light range such as Si may be used for the first
electrode.

[0031] According to this configuration, since the first electrode of the
non-light-transmissive material and the first reflection film are stacked
to form the ring-shaped first multilayer stopper portion, an area of the
first reflection film that is exposed inside the non-light-transmissive
first multilayer stopper portion is a light transmitting area for
incident light, and the first multilayer stopper portion can be used as
an aperture. By using such a variable wavelength interference filter and
measuring the quantity of light extracted by the variable wavelength
interference filter, accurate light quantity measurement can be carried
out.

[0032] In the variable wavelength interference filter, it is preferable
that the second electrode is provided on a surface of the second
substrate that faces the first substrate, that a portion of the second
electrode is stacked on an outer circumferential edge of the second
reflection film to form a ring-shaped second multilayer stopper portion,
and that an inner diameter dimension of the first multilayer stopper
portion is smaller than an inner diameter dimension of the second
multilayer stopper portion, as viewed in a plan view of the first
substrate and the second substrate.

[0033] According to this configuration, the inner diameter dimension of
the first multilayer stopper portion is made smaller than the inner
diameter dimension of the second multilayer stopper portion. That is, the
light transmitting area is prescribed by the inner diameter dimension of
the first multilayer stopper portion.

[0034] Generally, it is difficult to align two apertures having the same
inner diameter dimension in such a manner that the inner diameter
portions thereof match each other perfectly. If misalignment occurs, the
quantity of light transmitted changes, too. On the other hand, if the
inner diameter dimension of the first multilayer stopper portion is made
smaller than the inner diameter dimension of the second multilayer
stopper portion, as described above, the inner diameter portion of the
first multilayer stopper portion can be easily installed so that it is
situated on the inner circumferential side of the second multilayer
stopper portion, as compared with the case where the inner diameter of
the first multilayer stopper portion and the inner diameter of the second
multilayer stopper portion are made to match each other perfectly. Also,
since the first multilayer stopper portion with the smaller inner
diameter dimension prescribes the light transmitting area, the light
transmitting area can be prescribed easily and accurately. Thus, the
quantity of light transmitted through the light transmitting area can be
easily set to a desired value.

[0035] Another aspect of the invention is directed to an optical module
including the aforementioned variable wavelength interference filter, and
a light receiving unit which receives inspection target light transmitted
through the variable wavelength interference filter.

[0036] According to this aspect of the invention, in the variable
wavelength interference filter, the reflection films can be prevented
from sticking to each other with a simple configuration. Also, a
reduction in the optical performance of the reflection films can be
prevented and the resolution can be maintained highly accurately.
Therefore, in the optical module having such a variable wavelength
interference filter, highly accurate light quantity measurement can be
carried out by the light receiving unit.

[0037] Still another aspect of the invention is directed to an optical
analysis device including the aforementioned optical module, and an
analytical processing unit which analyzes an optical property of the
inspection target light based on light received by the light receiving
unit of the optical module.

[0038] According to this aspect of the invention, since the optical module
having the variable wavelength interference filter is provided, highly
accurate measurement can be carried out. As optical analytical processing
is carried out based on the result of this measurement, accurate
spectroscopic properties can be implemented.

BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Embodiments of the invention will be described with reference to
the accompanying drawings, wherein like numbers reference like elements.

[0040]FIG. 1 a block diagram showing a schematic configuration of a
colorimeter device according to a first embodiment of the invention.

[0041]FIG. 2 is a plan view of a first substrate of an etalon according
to the first embodiment.

[0042]FIG. 3 is a plan view of a second substrate of the etalon according
to the first embodiment.

[0043]FIG. 4 is a sectional view showing a schematic configuration of the
etalon according to the first embodiment.

[0044]FIG. 5 is a partial sectional view showing parts of an etalon
according to a first modification of the first embodiment.

[0045]FIG. 6 is a partial sectional view showing parts of an etalon
according to a second modification of the first embodiment.

[0046]FIG. 7 is a partial sectional view showing parts of the etalon
according to the second modification of the first embodiment.

[0047]FIG. 8 is a partial sectional view showing parts of an etalon
according to a third modification of the first embodiment.

[0048]FIG. 9 is a partial sectional view showing parts of an etalon
according to a fourth modification of the first embodiment.

[0049] FIG. 10 is a partial sectional view showing parts of an etalon
according to a fifth modification of the first embodiment.

[0050]FIG. 11 is a plan view of a first substrate of an etalon according
to a second embodiment of the invention.

[0051]FIG. 12 is a plan view of a second substrate of the etalon
according to the second embodiment.

[0052]FIG. 13 is a partial sectional view showing parts of the etalon
according to the second embodiment.

[0053]FIG. 14 is a partial sectional view showing parts of an etalon
according to a third embodiment of the invention.

[0054]FIG. 15 is a plan view of a first substrate of an etalon according
to a fourth embodiment of the invention.

[0055]FIG. 16 is a plan view of a second substrate of the etalon
according to the fourth embodiment.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

First Embodiment

[0056] Hereinafter, a first embodiment of the invention will be described
with reference to the drawings.

1. Schematic Configuration of Colorimeter Device

[0057]FIG. 1 is a block diagram showing a schematic configuration of a
colorimeter device 1 (optical analysis device) according to this
embodiment.

[0058] The colorimeter device 1 includes a light source device 2 which
emits light to an inspection target A, a colorimetric sensor 3 (optical
module), and a controller 4 which controls the overall operation of the
colorimeter device 1, as shown in FIG. 1. In this colorimeter device 1,
light emitted from the light source device 2 is reflected on the
inspection target A and the reflected inspection target light is received
by the colorimetric sensor 3. Based on a detection signal outputted from
the colorimetric sensor 3, the chromaticity of the inspection target
light, that is, the color of the inspection target A, is analyzed and
measured.

2. Configuration of Light Source Device

[0059] The light source device 2 includes a light source 21 and plural
lenses 22 (in FIG. 1, only one lens is shown), and emits white light
toward the inspection target A. The plural lenses 22 may include a
collimating lens. In such case, in the light source device 2, white light
emitted from the light source 21 is turned into parallel beams by the
collimating lens and is then emitted toward the inspection target A from
a projection lens, not shown. In this embodiment, the colorimeter device
1 having the light source device 2 is described as an example. However,
for example, in the case where the inspection target A is a light
emitting member such as a liquid crystal panel, a configuration without
having the light source device 2 may be employed.

3. Configuration of Colorimetric Sensor

[0060] The colorimetric sensor 3 includes an etalon 5 (variable wavelength
interference filter), a light receiving element 31 (light receiving unit)
which receives light transmitted through the etalon 5, and a voltage
control unit 6 which varies the wavelength of light to be transmitted at
the etalon 5, as shown in FIG. 1. The colorimetric sensor 3 has a
light-incident optical lens, not shown, which guides inward the reflected
light (inspection target light) reflected by the inspection target A, at
a position facing the etalon 5. In the colorimetric sensor 3, light with
a predetermined wavelength, of the inspection target light incident from
the light-incident optical lens, is spectrally separated by the etalon 5
and the separated light (filtered light) is received by the light
receiving element 31.

[0061] The light receiving element 31 includes plural photoelectric
converter elements and generates an electric signal corresponding to the
quantity of light received. The light receiving element 31 is connected
to the controller 4 and outputs the generated electric signal to the
controller 4 as a light receiving signal.

3-1. Configuration of Etalon

[0062]FIG. 2 is a plan view of a first substrate 51 of the etalon 5. FIG.
3 is a plan view of a second substrate 52 of the etalon 5. FIG. 4 is a
sectional view of the etalon 5, taken along arrow line IV-IV in FIG. 2
and FIG. 3. It should be noted that in FIG. 1, inspection target light
becomes incident on the etalon 5 from the bottom side of the drawing,
whereas in FIG. 4, inspection target light becomes incident from the top
side of the drawing.

[0063] As shown in FIG. 2 and FIG. 3, the first substrate 51 and the
second substrate 52 are optical members in the shape of a square plate as
viewed in a plan view, for example, with one side being 10 mm. As shown
in FIG. 4, this etalon 5 includes the first substrate 51 and the second
substrate 52. These substrates 51, 52 are bonded to each other and
integrally formed via a bonding layer 53 by siloxane bonding using a
plasma polymerized film or the like. Each of the two substrates 51, 52 is
made of, for example, various kinds of glass such as soda-lime glass,
crystalline glass, quartz glass, lead glass, potassium glass,
borosilicate glass, and non-alkaline glass, or crystal and the like.

[0064] Between the first substrate 51 and the second substrate 52, a fixed
mirror 54 (first reflection film) having a diameter dimension R1 and a
movable mirror 55 (second reflection film) having a diameter dimension R2
are provided, as shown in FIG. 2 and FIG. 4. Here, the fixed mirror 54 is
formed on a surface of the second substrate 52 that faces the first
substrate 51. The movable mirror 55 is formed on a surface of the first
substrate 51 that faces the second substrate 52. The fixed mirror 54 and
the movable mirror 55 are arranged to face each other across an
inter-mirror gap G1.

[0065] Moreover, an electrostatic actuator 56 for adjusting the
inter-mirror gap G1 between the mirrors 54, 55 is provided between the
first substrate 51 and the second substrate 52. The electrostatic
actuator 56 is formed in a ring shape, as viewed in a plan view in a
direction of substrate thickness (hereinafter referred to as a plan view
of the etalon), so as to cover an outer circumferential edge of each of
the mirrors 54, 55. The configuration of the electrostatic actuator 56
will be described in detail later.

3-1-1. Configuration of First Substrate

[0066] The first substrate 51 is formed by processing a glass base
material with a thickness of, for example, 500 μm, by etching. As
shown in FIG. 2 and FIG. 4, an electrode forming groove 511 and a mirror
fixing portion 512 are formed on the first substrate 51 by etching.

[0067] In the electrode forming groove 511, an electrode fixing surface
511A which is ring-shaped, as viewed in the plan view of the etalon, is
formed from an outer circumferential edge of the mirror fixing portion
512 to an inner circumferential wall surface of the electrode forming
groove 511, as shown in FIG. 2 and FIG. 4.

[0068] In the mirror fixing portion 512, a mirror fixing surface 512A that
is formed substantially in a cylindrical shape coaxial with the electrode
forming groove 511 and having a smaller diameter dimension than the
electrode forming groove 511 is provided on a surface on the side facing
the second substrate 52, as shown in FIG. 2 and FIG. 4.

[0069] On the mirror fixing surface 512A, the fixed mirror 54 formed by a
circular single layer of an AgC alloy that can cover the entire visible
light range as a spectrally separable wavelength range, is fixed. In this
embodiment, a mirror of a single layer of an AgC alloy is used as an
example of the fixed mirror 54. However, a TiO2--SiO2-based
dielectric multilayer film, a mirror of an Ag alloy other than AgC
alloys, or a multilayer film mirror including an Ag alloy and a
dielectric film may be used.

[0070] On the first substrate 51, a first electrode 561 is formed which
extends toward the outer circumferential edge of the mirror fixing
surface 512A from the electrode fixing surface 511A and which covers the
outer circumferential edge of the fixed mirror 54 formed on the mirror
fixing surface 512A.

[0071] The first electrode 561 is formed in a ring shape, as viewed in the
plan view of the etalon. The outer circumferential edge of the fixed
mirror 54 and the inner circumferential edge of the first electrode 561
are stacked in this order from the first substrate 51. Thus, a first
multilayer stopper portion 60 (shaded part in FIG. 2) formed in a ring
shape, as viewed in the plan view of the etalon, is configured. That is,
the first multilayer stopper portion 60 is formed along the
circumferential direction of an imaginary circle that centers on a center
point C1 (see FIG. 2) of the fixed mirror 54.

[0072] Since the first multilayer stopper portion 60 is provided on the
outer circumferential edge of the fixed mirror 54, a light transmitting
area Ar1 (see FIG. 2) of the fixed mirror 54 is exposed. A gap G2 between
the first multilayer stopper portion 60 and the movable mirror 55 is
smaller than the inter-mirror gap G1. Therefore, when the inter-mirror
gap G1 is reduced by the electrostatic actuator 56, the movable mirror 55
abuts the first multilayer stopper portion 60. Even when the mirrors 54,
55 are close to each other, the mirrors 54, 55 are prevented from
sticking to each other.

[0073] On the top surface of the first electrode 561, as shown in FIG. 4,
an insulating film 563 is formed in order to prevent a leak due to
discharge or the like between the first electrode 561 and a second
electrode 562 on the second substrate 52, which will be described later.
That is, the insulating film 563 also covers the first multilayer stopper
portion 60.

[0074] As the insulating film 563, SiO2, TEOS (tetraethoxysilane) or
the like can be used. Particularly, SiO2 having the same optical
properties as the glass substrate forming the first substrate 51 is
preferable. If SiO2 is used as the insulating film 563, since there
is no reflection or the like of light between the first substrate 51 and
the insulating film, the insulating film can be formed on the entire
surface of the first substrate 51 on the side facing the second substrate
52 after the first electrode 561 is formed on the first substrate 51.

[0075] The first electrode 561 is electrically conductive and
non-light-transmissive. The first electrode 561 is not particularly
limited as long as electrostatic attraction can be generated between the
first electrode 561 and the second electrode 562 by application of a
voltage between the first electrode 561 and the second electrode 562 on
the second substrate 52, which will be described later. However, in this
embodiment, an Au/Cr metal multilayer body is used.

[0076] An insulating film may also be formed on the second electrode 562,
which will be described later, similarly to the first electrode 561.

[0077] One first electrode line 561L is formed extending toward top right
from a portion of the outer circumferential edge of the first electrode
561 so as to follow a diagonal line across the first substrate 51, as
viewed in the plan view shown in FIG. 2.

[0078] A first electrode pad 561P is formed at a distal end of the first
electrode line 561L. The first electrode pad 561P is connected to the
voltage control unit 6 (see FIG. 1). At the time of driving the
electrostatic actuator 56, a voltage is applied to the first electrode
pad 561P by the voltage control unit 6 (see FIG. 1).

[0079] Here, a portion of the first substrate 51 where the electrode
forming groove 511 and the mirror fixing portion 512 are not formed
serves as a bonding surface 513 of the first substrate 51. As shown in
FIG. 4, the bonding layer 53 for bonding is formed on the bonding surface
513. For the bonding layer 53, a plasma polymerized film using
polyorganosiloxane as a principal material or the like can be used.

3-1-2. Configuration of Second Substrate

[0080] The second substrate 52 is formed by processing a glass base
material having a thickness of, for example, 200 μm, by etching. On
this second substrate 52, a circular displaced portion 521 centering on
the center point of the substrate, as viewed in the plan view of the
etalon shown in FIG. 3, is formed. This displaced portion 521 has a
connection holding portion 523 which is coaxial with a columnar movable
portion 522 that is movable toward and retreats from the first substrate
51, and which is formed in a circular ring shape, as viewed in the plan
view of the etalon, and holds the movable portion 522 movably in the
direction of the thickness of the second substrate 52, as shown in FIG. 3
and FIG. 4.

[0081] The displaced portion 521 is formed by forming a groove by etching
the flat plate-like glass base material as the forming material of the
second substrate 52. That is, the displaced portion 521 is formed by
forming a circular ring-shaped groove portion 523A for forming the
connection holding portion 523 by etching on the light incident side of
the second substrate 52 that does not face the first substrate 51.

[0082] The movable portion 522 is formed to a greater thickness dimension
than the connection holding portion 523. For example, in this embodiment,
the movable portion 522 is formed to 200 μm, which is the same
dimension as the thickness dimension of the second substrate 52. The
diameter dimension of the movable portion 522 is greater than the
diameter dimension of the mirror fixing portion 512 of the first
substrate 51.

[0083] On a surface of the movable portion 522 that faces the first
substrate 51, a movable surface 522A parallel to the mirror fixing
surface 512A on the first substrate 51 is provided. On the movable
surface 522A, the movable mirror 55 facing the fixed mirror 54, and the
second electrode 562 facing the first electrode 561 are formed. Here, the
second electrode 562 and the first electrode 561 form the electrostatic
actuator 56.

[0084] The movable mirror 55 is made of the same material as the fixed
mirror 54 and is formed with the diameter dimension R2 greater than the
diameter dimension R1 of the fixed mirror 54. The movable mirror 55 is
provided so as to overlap the fixed mirror 54, as viewed in the plan view
of the etalon.

[0085] The second electrode 562 is made of the same material as the first
electrode 561. Also, the second electrode 562 is formed in a ring shape,
as viewed in the plan view of the etalon, and is formed so that the inner
circumferential edge thereof covers the outer circumferential edge of the
movable mirror 55. The outer circumferential edge of the movable mirror
55 and the inner circumferential edge of the second electrode 562 are
stacked in this order from the second substrate 52. Thus, a second
multilayer stopper portion 70 (shaded part in FIG. 3) formed in a ring
shape, as viewed in the plan view of the etalon, is configured. That is,
the second multilayer stopper portion 70 is formed along the
circumferential direction of an imaginary circle centering on a center
point C2 (see FIG. 3) of the movable mirror 55.

[0086] Since the second multilayer stopper portion 70 is provided on the
outer circumferential edge of the movable mirror 55, a light transmitting
area Ar2 (see FIG. 3) of the movable mirror 55 is exposed. Since the
movable mirror 55 is larger than the fixed mirror 54, the light
transmitting area Ar2 of the movable mirror 55 is set to be greater than
the light transmitting area Ar1 of the fixed mirror 54. That is, the
inner diameter dimension of the second multilayer stopper portion 70 is
made greater than the inner diameter dimension of the first multilayer
stopper portion 60. Therefore, the quantity of light transmitted through
the etalon 5, of the inspection target light incident from the top side
of the second substrate 52, is prescribed by the inner diameter dimension
of the first multilayer stopper portion 60, that is, the light
transmitting area Ar1 of the fixed mirror 54.

[0087] For the second electrode 562, an Au/Cr metal multilayer body of the
same material as the first electrode 561 is used. However,
light-transmissive ITO (indium tin oxide) may also be used.

[0088] Moreover, the inner diameter dimension of the second multilayer
stopper portion 70 is made greater than the outer dimension R1 of the
first multilayer stopper portion 60. That is, the first multilayer
stopper portion 60 is provided at a position that it does not overlap the
second multilayer stopper portion 70, as viewed in a plan view in the
direction of substrate thickness of the etalon 5.

[0089] The connection holding portion 523 is a diaphragm surrounding the
periphery of the movable portion 522 and is formed to a thickness
dimension of, for example, 50 μm.

[0090] One second electrode line 562L is formed extending toward bottom
left from a portion of the outer circumferential edge of the second
electrode 562 so as to follow a diagonal line across the second substrate
52, as viewed in the plan view of the etalon shown in FIG. 3.

[0091] A second electrode pad 562P is formed at a distal end of the second
electrode line 562L. The second electrode pad 562P is connected to the
voltage control unit 6 (see FIG. 1). At the time of driving the
electrostatic actuator 56, a voltage is applied to the second electrode
pad 562P by the voltage control unit 6 (see FIG. 1).

[0092] Here, an area facing the bonding surface 513 of the first substrate
51, on the surface of the second substrate 52 that faces the first
substrate 51, serves as a bonding surface 524 of the second substrate 52.
On the bonding surface 524, the bonding layer 53 using polyorganosiloxane
as a principal material is provided, similarly to the bonding surface 513
of the first substrate 51.

3-2. Configuration of Voltage Control Unit

[0093] The voltage control unit 6 controls the voltage applied to the
first electrode 561 and the second electrode 562 of the electrostatic
actuator 56, based on a control signal inputted from the controller 4.

4. Configuration of Controller

[0094] The controller 4 controls overall operation of the colorimeter
device 1. As the controller 4, for example, a general-purpose personal
computer, personal digital assistant, computer for colorimetry or the
like can be used.

[0095] The controller 4 includes alight source control unit 41, a
colorimetric sensor control unit 42, a colorimetric processing unit 43
(analytic processing unit) and the like, as shown in FIG. 1.

[0096] The light source control unit 41 is connected to the light source
device 2. The light source control unit 41 outputs a predetermined
control signal to the light source device 2, for example, based on user's
setting input, and thus causes the light source device 2 to emit white
light of predetermined brightness.

[0097] The colorimetric sensor control unit 42 is connected to the
colorimetric sensor 3. The colorimetric sensor control unit 42 sets a
wavelength of light to be received by the colorimetric sensor 3, for
example, based on user's setting input, and outputs to the colorimetric
sensor 3 a control signal indicating that the quantity of light received
with this wavelength should be detected. Thus, based on the control
signal, the voltage control unit 6 of the colorimetric sensor 3 sets an
applied voltage to the electrostatic actuator 56 so that the wavelength
of light desired by the user will be transmitted.

[0098] The colorimetric processing unit 43 controls the colorimetric
sensor control unit 42 to alter the inter-mirror gap in the etalon 5 and
thus changes the wavelength of light transmitted through the etalon 5.
Also, the colorimetric processing unit 43 acquires the quantity of light
of the light transmitted through the etalon 5, based on a light receiving
signal inputted from the light receiving element 31. Based on the
quantity of light received with each wavelength that is acquired by the
above processing, the colorimetric processing unit 43 calculates
chromaticity of the light reflected by the inspection target A.

5. Advantages and Effects of First Embodiment

[0099] The etalon 5 according to the first embodiment has the following
advantages.

[0100] (1) The inner circumferential edges of the ring-shaped first
electrode 561 and second electrode 562 and the outer circumferential
edges of the circular fixed mirror 54 and movable mirror 55 are stacked
to form the multilayer stopper portions 60, 70. Thus, since the dimension
of the gap G2 between the multilayer stopper portions 60, 70 and the
mirrors 54, 55 is smaller than the dimension of the inter-mirror gap G1,
the multilayer stopper portions 60, 70 contact an opposing surface when
the dimension of the inter-mirror gap G1 is reduced. Therefore, there is
no sticking of the mirrors 54, 55. The mirrors 54, 55 can be prevented
from sticking to each other.

[0101] Moreover, since the multilayer stopper portions 60, 70 are formed
by stacking the electrodes 561, 562 and the mirrors 54, 55, the
protrusion having the configuration of the related art need not be
provided separately. The manufacturing process can be simplified and a
simple configuration can be realized. That is, the multilayer stopper
portions 60, 70 can be easily formed simply by implementing the process
of forming the electrodes 561, 562 and the process of forming the mirrors
54, 55.

[0102] (2) The first electrode 561 and the second electrode 562 are drive
electrodes and therefore can also serve as the electrostatic actuator 56
which changes the dimension of the inter-mirror gap G1. That is, in the
process of manufacturing the etalon 5, the process of separately
providing the protrusion having the configuration of the related art can
be eliminated. Thus, the manufacturing process can be simplified and a
simple structure can be realized.

[0103] (3) Since the multilayer stopper portions 60, 70 are configured
with the electrodes 561, 562 stacked on the mirrors 54, 55, the
electrodes 561, 562 can securely protect the edges of the mirrors 54, 55
and prevent deterioration of the mirrors 54, 55.

[0104] (4) Since the electrodes 561, 562 of the non-light-transmissive
material and the mirrors 54, 55 are stacked to form the multilayer
stopper portions 60, 70, the smaller one of the areas of the mirrors 54,
55 exposed inside the non-light-transmissive multilayer stopper portions
60, 70 is the light transmitting area for incident light. Moreover, in
this embodiment, since diameter dimension R1 of the fixed mirror 54 is
smaller than the diameter dimension R2 of the movable mirror 55, the
exposed light transmitting area Ar1 of the fixed mirror 54 is the light
transmitting area for incident light. Therefore, in the manufacturing
process, even when it is difficult to form the diameter dimensions R1, R2
of the mirrors 54, 55 to the same dimension, the light transmitting area
Ar1 can be prescribed easily and accurately by forming the multilayer
stopper portions 60, 70. Thus, the quantity of light transmitted through
the light transmitting area Ar1 can be easily set to a desired value.

[0105] (5) The outer dimension R1 of the first multilayer stopper portion
60 is made smaller than the inner diameter dimension of the second
multilayer stopper portion 70, and the first multilayer stopper portion
60 and the second multilayer stopper portion 70 do not overlap each
other, as viewed in a plan view where the etalon 5 is viewed from a
direction of substrate thickness. Therefore, when a large stress is
applied in the direction of the substrate thickness of the etalon 5, the
area of the contact site is larger and the pressure can be dispersed
better than when only the first multilayer stopper portion 60 is formed
or when the first multilayer stopper portion 60 and the second multilayer
stopper portion contact each other. Therefore, the first multilayer
stopper portion 60 and the second multilayer stopper portion 70 can be
prevented from being damaged by stress.

First Modification of First Embodiment

[0106]FIG. 5 is a partial sectional view showing parts of the etalon 5
according to a first modification of the first embodiment.

[0107] In the first embodiment, the first multilayer stopper portion 60
and the second multilayer stopper portion 70 are provided at positions
that do not overlap each other, as viewed in the plan view of the etalon
5. However, as a modification of this, a configuration as shown in FIG. 5
may be employed. That is, the first multilayer stopper portion 60 and the
second multilayer stopper portion 70 are provided at such positions that
a portion of the first multilayer stopper portion 60 and a portion of the
second multilayer stopper portion 70 overlap each other, as viewed in the
plan view. The first multilayer stopper portion 60 and the second
multilayer stopper portion 70 abut each other, thereby preventing the
mirrors 54, 55 from contacting and sticking to each other.

[0108] Again, in such a configuration, the inner circumferential edge of
the first multilayer stopper portion has a smaller diameter dimension
than the inner circumferential edge of the second multilayer stopper
portion 70 and is provided inside the inner circumferential edge of the
second multilayer stopper portion. Thus, the light transmitting area for
inspection target light transmitted through the etalon 5 can be
prescribed.

[0109] Also, in this modification, since the first multilayer stopper
portion 60 and the second multilayer stopper portion 70 are formed to
overlap each other in a plan view of the etalon, the gap G2 is the
dimension between the multilayer stopper portions 60, 70.

[0110] According to this modification, when the dimension of the
inter-mirror gap G1 is reduced, the multilayer stopper portions 60, 70
contact each other. In this case, in the state where the movement of the
movable portion 522 is regulated by the contact of the multilayer stopper
portions 60, 70, the space between the mirrors 54, 55 is greater than in
the first embodiment. Therefore, contacting and sticking of the mirrors
54, 55 can be prevented more securely.

[0111] Also, in this modification, an insulating film may be formed to
cover the first electrode 561 or formed to cover the second electrode 562
only, as in the first embodiment. Alternatively, an insulating film may
be formed to cover both the first electrode 561 and the second electrode
562.

Second Modification of First Embodiment

[0112]FIG. 6 is a partial sectional view showing parts of the etalon 5
according to a second embodiment of the first embodiment.

[0113] The multilayer stopper portions 60, 70 in the first embodiment are
configured with the mirrors 54, 55 and the electrodes 561, 562 stacked in
this order from the substrates 51, 52. However, as a modification, the
electrodes 561, 562 and the mirrors 54, 55 may be stacked in order from
the substrates 51, 52, as shown in FIG. 6.

[0114] In the manufacturing process of the etalon 5 with such a
configuration, the mirrors 54, 55 are deposited after the electrodes 561,
562 are deposited. Therefore, the process of forming the mirrors 54, 55,
which can easily be deteriorated in optical properties such as
transmittance and reflectance by such factors as ambient temperature, can
be shifted to a later stage, and damage to the mirrors 54, 55 during the
manufacturing process can be prevented securely.

[0115] Also, for example, if the fixed mirror 54 is formed as a dielectric
multilayer film, a portion or the entirety of the dielectric multilayer
film may be formed on the first electrode 561 and the second electrode
562 and may be used as an insulating layer. With such a configuration,
the process of forming the insulating layer can be omitted and the
manufacturing process can be simplified further.

[0116]FIG. 6 shows the configuration in which the first multilayer
stopper portion 60 and the second multilayer stopper portion 70 abut each
other to prevent the mirrors 54, 55 from contacting and sticking to each
other, as in the first modification. However, as in the first embodiment,
the first multilayer stopper portion 60 and the second multilayer stopper
portion 70 may be provided at positions that do not overlap each other,
as viewed in the plan view of the etalon 5.

[0117] Alternatively, in the above configuration, mirror protection films
59 may be formed to cover the mirrors 54, 55 and the multilayer stopper
portions 60, 70, as shown in FIG. 7. Silicon (Si) oxide films are used as
the mirror protection films 59. Also, aluminum (Al) oxide films,
magnesium (Mg) fluoride films and the like can be used.

[0118] With such a configuration, when the inter-mirror gap G1 is reduced
and the first multilayer stopper portion 60 and the second multilayer
stopper portion 70 contact each other, the mirror protection films 59
cover the mirrors 54, 55 and therefore can securely prevent damage to the
mirrors 54, 55. Moreover, since the mirror protection films 59 cover the
outer circumferential edges of the mirrors 54, 55, which tend to be
deteriorated or detached easily, deterioration and detachment of the
mirrors 54, 55 can be prevented.

Third Modification of First Embodiment

[0119]FIG. 8 is a partial sectional view showing parts of the etalon 5
according to a third modification of the first embodiment.

[0120] In the first embodiment, the insulating film 563 covering the first
electrode 561 is formed. However, insulative mirror protection films 59
covering the mirrors 54, 55 and the electrodes 561, 562 may be formed.

[0121] With such a configuration, the mirror protection films 59 can
restrain deterioration of the mirrors 54, 55 and can also prevent
discharge and leak between the first electrodes 561 and the second
electrode 562.

Fourth Modification of First Embodiment

[0122]FIG. 9 is a partial sectional view showing parts of the etalon 5
according to a fourth modification of the first embodiment.

[0123] In the third modification of the first embodiment, the mirror
protection films 59 are formed to cover the mirrors 54, 55 and the
multilayer stopper portions 60, 70. However, at the multilayer stopper
portions 60, 70, the mirror protection films 59 may be formed between the
electrodes 561, 562 and the mirrors 54, 55 and thus formed to cover the
mirrors 54, 55.

[0124] According to this modification, the mirror protection films 59 can
restrain deterioration of the mirrors 54, 55.

Fifth Modification of First Embodiment

[0125] FIG. 10 is a partial sectional view showing parts of the etalon 5
according to a fifth modification of the first embodiment.

[0126] In the first embodiment, the multilayer stopper portions 60, 70 are
formed on both the first substrate 51 and the second substrate 52.
However, a configuration in which the first multilayer stopper portion 60
is provided only on the first substrate 51 may be employed.

[0127] FIG. 10 illustrates a case where the diameter dimensions of the
mirrors 54, 55 are formed to the same dimension, as in the first
modification. However, the diameter dimensions of the mirrors 54, 55 may
be different, as in the first embodiment.

[0128] Also, in this modification, mirror protection films may be provided
to cover the mirrors 54, 55. Moreover, an insulating film may be formed
to cover the first electrode 561 or formed to cover the second electrode
562 only. Alternatively, an insulating film may be formed to cover both
the first electrode 561 and the second electrode 562.

[0129] Moreover, a configuration in which the second multilayer stopper
portion 70 is provided only on the second substrate 52, without providing
the first multilayer stopper portion 60 on the first substrate 51, may be
employed.

Second Embodiment

[0130] Hereinafter, a second embodiment of the invention will be described
with reference to FIG. 11 to FIG. 13.

[0131]FIG. 11 is a plan view of a first substrate 51A of an etalon 5A
according to this embodiment. FIG. 12 is a plan view of a second
substrate 52A. In FIG. 11, and FIG. 12, for convenience of illustration,
only electrodes 561A, 562A and mirrors 54, 55 formed on substrates 51A,
52A are shown. FIG. 13 is a partial sectional view showing parts of the
etalon 5A taken along arrow line XIII-XIII in FIG. 11 and FIG. 12.

[0132] The etalon 5A of this embodiment has a similar configuration to the
etalon 5 of the first embodiment but it is different in that the etalon
5A of this embodiment has a first drive electrode 571 and a second drive
electrode 572 in addition to the first electrode 561A and the second
electrodes 562A, and that the first drive electrode 571 and the second
drive electrode 572 form the electrostatic actuator 56.

[0133] In the following description, the same components as in the first
embodiment are denoted by the same reference numerals and will not be
described further in detail.

[0134] The diameter dimensions R1, R2 of the mirrors 54, 55 in this
embodiment may be formed to the same dimension, and the light
transmitting areas Art, Ar2 of the mirrors 54, 55 (areas toward the
mirrors 54, 55 from the chain dotted line in FIG. 13) may be formed to
the same size. In this case, the light transmitting area for inspection
target light transmitted through the etalon 5A is prescribed by the light
transmitting areas Art, Ar2 of the mirrors 54, 55.

[0135] A first multilayer stopper portion 60A is configured by stacking
the first electrode 561A and the fixed mirror 54 in this order from the
first substrate 51A, as shown in FIG. 13.

[0136] A second multilayer stopper portion 70A is configured by stacking
the second electrodes 562A and the movable mirror 55 in this order from
the second substrate 52A, as shown in FIG. 13.

[0137] The first multilayer stopper portion 60A and the second multilayer
stopper portion 70A may be configured by stacking the mirrors 54, 55 and
the electrodes 561A, 562A in this order from the substrates 51A, 52A, as
in the first embodiment.

[0138] The first electrode 561A and the second electrodes 562A are for
holding electric charge and function as electrostatic capacitance
measuring electrodes. Therefore, the insulating films 563 are provided on
the first electrode 561A and the second electrodes 562A, as shown in FIG.
13, to prevent leak between the electrodes 561A, 562A. The insulating
films 563 are also formed on the fixed mirror 54 and the movable mirror
55 and also function as mirror protection films. That is, even when the
inter-mirror gap G1 is reduced and the multilayer stopper portions 60A,
70A contact each other, damage to the mirrors 54, 55 is prevented.

[0139] The first electrode 561A is formed only on the mirror fixing
surface 512A of the mirror fixing portion 512. The second electrodes 562A
is formed only on the movable surface 522A of the movable portion 522.

[0140] The quantity of electric charge held by the first electrode 561A is
detected by the voltage control unit 6 (see FIG. 1) via the first
electrode pad 561P (see FIG. 11). The quantity of electric charge held by
the second electrodes 562A is detected by the voltage control unit 6 (see
FIG. 1) via the second electrode pad 562P (see FIG. 12). Based on the
detected electrostatic capacitance, the voltage control unit 6 (see FIG.
1) calculates the gap and applies a voltage for setting the inter-mirror
gap G1 to a desired gap, to the first drive electrode 571 and the second
drive electrode 572. That is, the inter-mirror gap G1 is accurately set
to a desired gap.

[0141] Each of the first drive electrode 571 and the second drive
electrode 572 is formed in a C-shape as viewed in a plan view of the
etalon, as shown in FIG. 11 and FIG. 12. The second drive electrode 572
is formed on the surface of the connection holding portion 523 that faces
the first substrate 51A. The first drive electrode 571 is formed on the
surface of the first substrate 51A that faces the second drive electrode
572.

[0142] The first drive electrode 571 is formed outside the first electrode
561A, centering on the center point C1 of the fixed mirror 54 and
concentric with the first electrode 561A, as shown in FIG. 11. One first
drive electrode line 571L is formed extending toward top left from a
portion on the outer circumferential edge of the first drive electrode
571 so as to follow a diagonal line on the first substrate 51A, as viewed
in the plan view of FIG. 11.

[0143] A first drive electrode pad 571P is formed at the distal end of the
first drive electrode line 571L. The first drive electrode pad 571P is
connected to the voltage control unit 6 (see FIG. 1). At the time of
driving the electrostatic actuator 56, a voltage is applied to the first
drive electrode pad 571P by the voltage control unit 6 (see FIG. 1).

[0144] The second drive electrode 572 is formed outside the second
electrode 562A, centering on the center point C2 of the movable mirror 55
and concentric with the second electrode 562A, as shown in FIG. 12. One
second drive electrode line 572L is formed extending toward bottom left
from a portion on the outer circumferential edge of the second drive
electrode 572 so as to follow a diagonal line on the second substrate
52A, as viewed in the plan view of FIG. 12.

[0145] A second drive electrode pad 572P is formed at the distal end of
the second drive electrode line 572L. The second drive electrode pad 572P
is connected to the voltage control unit 6 (see FIG. 1). At the time of
driving the electrostatic actuator 56, a voltage is applied to the second
drive electrode pad 572P by the voltage control unit 6 (see FIG. 1).

[0146] The etalon 5A according to the second embodiment has the following
advantages as well as the advantages of the first embodiment.

[0147] According to this embodiment, the first electrode 561A and the
second electrodes 562A function as electrostatic capacitance measuring
electrodes. The voltage control unit 6 calculates the gap based on the
detected electrostatic capacitance and applies a voltage for setting the
inter-mirror gap G1 to a desired gap, to the first drive electrode 571
and the second drive electrode 572. Thus, the inter-mirror gap G1 can be
accurately set to a desired gap.

[0148] In the process of manufacturing the etalon 5A, the multilayer
stopper portions 60A, 70A can be easily formed by the process of forming
the mirrors 54, 55 and the process of forming the first electrode 561A
and the second electrodes 562A (electrostatic capacitance measuring
electrodes).

Third Embodiment

[0149] Hereinafter, a third embodiment of the invention will be described
with reference to FIG. 14.

[0150]FIG. 14 is a partial sectional view showing parts of an etalon 5B
according to this embodiment.

[0151] Again, the etalon 5B of this embodiment has the first drive
electrode 571 and the second drive electrode 572 in addition to a first
electrode 561B and a second electrode 562B, as in the second embodiment.
The first drive electrode 571 and the second drive electrode 572 form the
electrostatic actuator 56.

[0152] In the following description, the same components as in the first
embodiment are denoted by the same reference numerals and will not be
described further in detail. The first drive electrode 571 and the second
drive electrode 572 have the same configuration as in the second
embodiment and therefore will not be described further.

[0153] The first multilayer stopper portion 60A and the second multilayer
stopper portion 70A in this embodiment are configured by stacking the
electrodes 561B, 562B and the mirrors 54, 55 in this order from the
substrates 51A, 52A, as in the second embodiment.

[0154] Also, the multilayer stopper portions 60A, 70A may be configured by
stacking the mirrors 54, 55 and the electrodes 561B, 562B in this order
from the substrates 51A, 52A, as in the first embodiment.

[0155] The first electrode 561B and the second electrode 562B function as
electric charge removing electrodes for removing an electric charge
stored in the mirrors 54, 55. Therefore, in this embodiment, the first
electrode line 561L and the second electrode line 562L formed in the
first embodiment are connected to a ground and the electric potential
difference between the first electrode 561B and the second electrode 562B
is set to be 0.

[0156] It is also possible to use one of the first electrode 561B and the
second electrode 562B as an electric charge removing electrode.

[0157] The etalon 5B according to the third embodiment has the following
advantages as well as the advantages of the first embodiment.

[0158] According to this embodiment, the first electrode 561B and the
second electrode 562B function as electric charge removing electrodes for
removing electric charge in the mirrors 54, 55. Moreover, when the
dimension of the inter-mirror gap G1 is reduced and the multilayer
stopper portions 60A, 70A contact each other, an electric charge held in
the mirrors 54, 55 can be released from the first electrode 561B and the
second electrode 562B (electric charge removing electrodes) of the
multilayer stopper portions 60A, 70A. Therefore, electrostatic attraction
due to an electric charge held in each of the mirrors 54, 55 does not
occur and the inter-mirror gap G1 can be accurately set to a desired gap
dimension.

Fourth Embodiment

[0159] Hereinafter, a fourth embodiment of the invention will be described
with reference to FIG. 15 and FIG. 16.

[0160]FIG. 15 is a plan view showing a first substrate 51B of an etalon
5C according to this embodiment. FIG. 16 is a plan view showing a second
substrate 52B of the etalon 5C. In FIG. 15 and FIG. 16, as in FIG. 11 and
FIG. 12, only electrodes 561C, 562C and mirrors 54, 55 formed on the
substrates 51B, 52B are shown for convenience of illustration.

[0161] The etalon 5C of this embodiment is different in that multilayer
stopper portions 60B, 70B are formed at equal intervals along the
circumferential direction of imaginary circles centering on the center
points C1, C2 of the mirrors 54, 55, whereas the multilayer stopper
portions 60, 70 in the first embodiment are ring-shaped.

[0162] In the following description, the same components as in the first
embodiment are denoted by the same reference numerals and will not be
described further in detail.

[0163] On a first electrode 561C of the etalon 5C according to this
embodiment, four first extending portions 561C2 extending at intervals of
90 degrees are formed in the circumferential direction of a first ring
portion 561C1 of the first electrode 561C, as shown in FIG. 15.
Specifically, the first extending portions 561C2 extend toward the center
point C1 of the fixed mirror 54 from the first ring portion 561C1, along
the diagonal lines across the first substrate 51B. As the distal end
sides of the four first extending portions 561C2 are stacked on the outer
circumferential edge of the fixed mirror 54, four first multilayer
stopper portions 60B are formed.

[0164] That is, the first multilayer stopper portions 60B are provided at
intervals of 90 degrees along the circumferential direction of the
imaginary circle (the first ring portion 561C1 of the first electrode
561C) centering on the center point C1 of the fixed mirror 54, as shown
in FIG. 15. In other words, the four first multilayer stopper portions
60B are formed with point symmetry about the center point C1 of the fixed
mirror 54 as the center of symmetry.

[0165] On a second electrode 562C, four second extending portions 562C2
extending at intervals of 90 degrees are formed in the circumferential
direction of a second ring portion 562C1 of the second electrode 562C, as
shown in FIG. 16. Specifically, the second extending portions 562C2
extend toward the center point C2 of the movable mirror 55 from the
second ring portion 562C1, along the center lines (chain dotted lines in
FIG. 16) of the second substrate 52B. Since the distal end sides of the
four second extending portions 562C2 are stacked on the outer
circumferential edge of the movable mirror 55, four second multilayer
stopper portions 70B are formed.

[0166] That is, the second multilayer stopper portions 70B are provided at
intervals of 90 degrees along the circumferential direction of the
imaginary circle (the second ring portion 562C1 of the second electrode
562C) centering on the center point C2 of the movable mirror 55, as shown
in FIG. 16. In other words, the four second multilayer stopper portions
70B are formed with point symmetry about the center point C2 of the
movable mirror 55 as the center of symmetry.

[0167] Moreover, the second multilayer stopper portions 70B are formed at
positions that are shifted 45 degrees respectively from the first
multilayer stopper portions 60B about the center points C1, C2 of the
mirrors 54, 55, as viewed in the plan view of the etalon. Therefore, the
second multilayer stopper portions 70B are formed at positions that do
not overlap the first multilayer stopper portions 60B.

[0168] In the above configuration, when the inter-mirror gap G1 (see FIG.
4) is reduced, the second multilayer stopper portions 70B contact the
fixed mirror 54, and the first multilayer stopper portions 60B contact
the movable mirror 55. Thus, the mirrors 54, 55 are prevented from
contacting each other.

[0169] Insulating films may be provided on the electrodes 561C, 562C of
this embodiment. Also, the third modification and the fourth modification
of the first embodiment may be applied to this embodiment.

[0170] The multilayer stopper portions 60B, 70B of this embodiment are
provided at intervals of 90 degrees along the circumferential direction
of the imaginary circles. However, the multilayer stopper portions 60B,
70B may be provided, for example, at intervals of 180 degrees. It
suffices that the multilayer stopper portions 60B, 70B are provided at
equal intervals.

[0171] Moreover the multilayer stopper portions 60B, 70B are formed at
positions that do not overlap each other, as viewed in the plan view of
the etalon. However, the multilayer stopper portions 60B, 70B may be
formed in such a manner as to overlap each other.

[0172] As the stacking order of the multilayer stopper portions 60B, 70B
of this embodiment, the stacking order of the multilayer stopper portions
60A, 70A in the first modification of the first embodiment, the second
embodiment, and the third embodiment may be employed. In this case, if
mirror protection films are provided on the mirrors 54, 55, damage to the
mirrors 54, 55 can be prevented even when the multilayer stopper portions
60B, 70B contact the mirrors 54, 55, respectively.

[0173] Moreover, the mirrors 54, 55 of this embodiment may be made of an
Ag alloy, thereby functioning as drive electrodes. The first electrode
561C and the second electrode 562C, and the first electrode line 561L and
the second electrode line 562L may be made to function as electrode lines
connected to the mirrors 54, 55. In this case, a voltage applied from the
electrodes pads 561P, 562P is applied to the mirrors 54, 55 via the
electrode lines. Thus, electrostatic attraction is generated between the
mirrors 54, 55 and the inter-mirror gap can be changed.

[0174] The etalon 5C according to the fourth embodiment has the following
advantages as well as the advantages of the first embodiment.

[0175] According to this embodiment, since the multilayer stopper portions
60B, 70B are provided at equal intervals along the circumferential
direction of the imaginary circles centering the center point C1, C2 of
the mirrors 54, 55, the multilayer stopper portions 60B, 70B and the
mirrors 54, 55 facing the multilayer stopper portions 60B, 70B contact
each other and the contact area can be made smaller than in the first
embodiment. Thus, attraction at the contact portion can be prevented and
the gap G1 between the mirrors 54, 55 can be accurately set to a desired
gap dimension.

Modification of Embodiments

[0176] The invention is not limited to the above embodiments and includes
modifications and improvements within a range that allows achievement of
the objects of the invention.

[0177] In the embodiments, the first and second multilayer stopper
portions 60, 70 are provided on the substrates 51, 52. However, a
configuration in which a multilayer stopper portion is provided only on
one of the substrates may be employed, as in the fifth modification of
the first embodiment.

[0178] In the first embodiment and the third embodiment, the multilayer
stopper portions 60, 70 are ring-shaped. However, the multilayer stopper
portions may be formed at equal intervals along the circumferential
direction of imaginary circles centering on the center points C1, C2 of
the mirrors 54, 55, as in the fourth embodiment.

[0179] In the third embodiment, the electric potential difference between
the first electrode 561B and the second electrode 562B is set to be 0.
However, an equal potential may be achieved by electrical connection of
the mirrors 54, 55 as the mirrors 54, 55 contact each other.

[0180] In the embodiments, the electrostatic actuator 56 is described as
an example of the configuration for changing the inter-mirror gap G1.
However, an electromagnetic actuator including an electromagnetic coil
through which a current flows and a permanent magnet which moves in
relation to the electromagnetic coil by an electromagnetic force may be
used. With such a configuration, a current flows through the
electromagnetic coil, and the permanent magnet moves toward the
electromagnetic coil by an electromagnetic force due to a magnetic flux
from the permanent magnet and interaction between this magnetic flux and
the current. Thus, a displaced portion changes. Alternatively, a
configuration in which a piezoelectric element that can expand and
contract by voltage application is provided between substrates may be
employed.

[0181] In the embodiments, the bonding surfaces 513, 524 are bonded by the
bonding layer 53. However, the bonding configuration is not limited to
this. Any bonding method may be used. For example, so-called
room-temperature activated bonding may be used, in which the bonding
layer 53 is not formed and the bonding surfaces 513, 524 are activated
and the activated bonding surfaces 513, 524 are superimposed and
pressurized for bonding.

[0182] In the embodiments, by way of example, the mirror fixing surface
512A of the mirror fixing portion 512 that faces the movable substrate 52
is formed more closely to the movable substrate 52 than the electrode
fixing surface 511A is. However, the configuration of these surfaces is
not limited to this example. The height positions of the electrode fixing
surface 511A and the mirror fixing surface 512A are properly set, based
on the dimension of the gap between the fixed mirror 54 fixed to the
mirror fixing surface 512A and the movable mirror 55 formed on the
movable substrate 52, the dimension between the first electrode 561 and
the second electrode 562, the thickness dimensions of the fixed mirror 54
and the movable mirror 55, and the like. Therefore, for example, a
configuration in which the electrode fixing surface 511A and the mirror
fixing surface 512A are formed on the same plane, or a configuration in
which a mirror fixing groove in the shape of a cylindrical groove is
formed at a center part of the electrode fixing surface 511A, with a
mirror fixing surface formed on a bottom surface of the mirror fixing
groove, may be employed.

[0183] In the embodiment, the colorimetric sensor 3 is described as an
example of the optical module of the invention, and the colorimeter
device 1 having the colorimetric sensor 3 is described as an example of
the optical analysis device. However, the optical module and the optical
analysis device are not limited to these. For example, a gas sensor which
detects light absorbed by a gas, of incident light, as the gas flows into
the sensor, may be used as the optical module of the invention. A gas
detecting device which, with such a gas sensor, analyzes and determines
the gas flowing into the sensor, may be used as the optical analysis
device of the invention. Moreover, the optical analysis device may be a
spectroscopic camera, spectroscopic analyzer or the like having such an
optical module.

[0184] It is also possible to transmit data via light of each wavelength
by changing the intensity of light of each wavelength with time. In this
case, light of a specific wavelength is spectrally separated by the
etalon 5 provided in the optical module and received by the light
receiving unit. Thus, data to be transmitted via the light of the
specific wavelength can be extracted. If light data of each wavelength is
processed by an optical analysis device having such an optical module for
data extraction, optical communication can be carried out.